private WcsSolution Solve(CorresponencePoint a, CorresponencePoint b)
{
WcsSolution s = new WcsSolution();
Vector2d center = new Vector2d(width / 2, height / 2);
Vector2d temp = a.Image - b.Image;
double imageLength = temp.Length;
double angularSperation = CAAAngularSeparation.Separation(a.Celestial.RA, a.Celestial.Dec, b.Celestial.RA, b.Celestial.Dec);
// Degrees per pixel
s.Scale = angularSperation / imageLength;
double imageRotation = Math.Atan2(temp.X, temp.Y) / Math.PI * 180;
temp = center - b.Image;
double centerRotation = Math.Atan2(temp.X, temp.Y) / Math.PI * 180;
s.OffsetX = width / 2;
s.OfsetY = height / 2;
Coordinates cent = a.Celestial;
int iters = 4;
while (iters-- > 0)
{
// Calculate Center
Vector2d tanA = Coordinates.RaDecToTan(cent, a.Celestial);
Vector2d tanB = Coordinates.RaDecToTan(cent, b.Celestial);
temp = tanA - tanB;
double tanLength = temp.Length;
s.Scale = (tanLength / Math.PI * 180) / imageLength;
double tanRotation = Math.Atan2(temp.X, temp.Y) / Math.PI * 180;
double tRotRad = -((imageRotation - tanRotation) / 180 * Math.PI);
Vector2d centerDistA = center - a.Image;
double centerRotaionA = Math.Atan2(centerDistA.X, centerDistA.Y);
double ratio = tanLength / imageLength;
double tanCx = tanA.X + Math.Sin(centerRotaionA + tRotRad) * ratio * centerDistA.Length;
double tanCy = tanA.Y + Math.Cos(centerRotaionA + tRotRad) * ratio * centerDistA.Length;
Vector2d result = Coordinates.TanToRaDec(cent, new Vector2d(tanCx, tanCy));
s.CenterX = result.X;
s.CenterY = result.Y;
cent = Coordinates.FromRaDec(result.X, result.Y);
}
double positionAngle = CAAAngularSeparation.PositionAngle(s.CenterX, s.CenterY, b.Celestial.RA, b.Celestial.Dec);
s.Rotation = -((centerRotation - positionAngle));
s.Flip = false;
return(s);
}